Number of Subsequences That Satisfy the Given Sum Condition LeetCode solution in Java

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class Solution {
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  public int numSubseq(int[] nums, int target) {
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    int n = nums.length;
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    int i = 0, j = n - 1;
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    int mod = (int) 1e9 + 7;
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    Arrays.sort(nums);
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    int[] pow = new int[n];
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    pow[0] = 1;
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    int count = 0;
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    for (int z = 1; z < n; z++) {
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      pow[z] = (pow[z - 1] * 2) % mod;
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    }
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    while (i <= j) {
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      if ((nums[i] + nums[j]) <= target) {
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        count = (count + pow[j - i]) % mod;
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        i++;
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      } else if ((nums[i] + nums[j]) > target) j--;
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    }
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    return count;
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  }
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}